1. Field of the Invention
The present invention relates to a directional coupler used in a microwave band or the like.
2. Description of Related Art
A directional coupler is widely used in order to carry out monitoring of electric power. As a directional coupler, there is a directional coupler having a structure of arranging two lines in a vertical direction (for example, refer to the following nonpatent reference 1). Because two lines are thus arranged in a vertical direction, coupling (broadside coupling) occurs electrically. As a result, a directional coupler can be implemented.